A passive solar water heating system does not have any moving parts or requires any pumping and piping assemblies which call for recirculation of the heat transfer fluid and the like. As a result, a passive solar water heating system is highly desirable if it can satisfy the requirements of a typical household user, such as in the Southwest United States and elsewhere in the United States where the available solar energy is capable of supplying almost all the heated water needs.
As it is well known, an active solar water heating system is a fairly expensive heating system and is only affordable because of the various tax credit incentives which have been provided for installation of these systems in a typical household. However, with the proposed elimination of these subsidies, the competitive advantage of a passive solar water heating system is clearly evident. Nevertheless, a passive solar water heating system has not been available which would be readily assembled and readily useful for a number of households, such as for the Southwest United States. Because of the fairly expensive installation techniques, these assemblies have been prohibitive to the economically less well positioned population.